keep it secret
Me ha pedido mantenerlo en secreto.
He asked me to keep it a secret.
Le prometí mantenerlo en secreto.
I promised to keep it a secret.
Ya sabes, hemos de mantenerlo en secreto hasta el último momento.
You know, we have to keep it a secret until the very last moment.
— Juego sucio (Infernal Affairs) (2002)
No podemos mantenerlo en secreto indefinidamente.
We can't keep it a secret indefinitely.
Prometí mantenerlo en secreto.
I promised to keep it a secret.